1. Field of the Invention
The present invention relates to a dust collector used in a hopper dryer, and more particularly to a dust collector for removing dust entrained in waste dry gas exhausted from a dry furnace which is designed to dehumidify material such as plastic pellets.
2. Prior Art
In treating powdery substances in a plastic molding process, a cyclone in usually employed as a dust collector. The cyclone is a conical vessel wherein airborne dust is extracted via centrifugal force. More specifically, airborne dust is urged to come down along the wall of the vessel by the force of gravity and is collected at the bottom thereof. Then, purified air is blown out of the vessel through the top thereof.
However, the method which uses cyclones described above has disadvantages such as lightweight dust is likely to be trapped in the air because the upstream air overcome the weight of the dust and then diffuses into the atmosphere, causing the environment to be contaminated. Also, if the amount of the air is too small, airborne dust is difficult to separate therefrom. To overcome these problems and increase dust collect efficiency, a small-size cyclone is used. However, pressure loss becomes greater, and the expected collection efficiency cannot be achieved.